PRESSURE REDUCING VALVES

PRESSURE REDUCING VALVES Ensure reliable and stable pressure for smooth-running water systems Reliance Water Controls Ltd A Reliance Worldwide Company Worcester Road, Evesham, Worcestershire, WR11 4RA, UK UK - Freephone: 0800 389 5931 Freefax: 0800 389 5932 Outside UK - Tel: +44 (0) 1386 712400 Fax: +44 (0) 1386 712401 The Safety Valve Specialist Email: sales@rwc.co.uk

Pressure control: solving water system problems The water systems in domestic, commercial and industrial properties can present unique problems and challenges as plumbing fittings become ever more sophisticated. The water supply pressure in the UK can vary from 1bar to 20bar (or even higher in some low usage areas). The water pressure will also tend to vary through the day, for instance at high usage times (typically mornings and late afternoons) the pressure may drop by comparison with low water usage times (throughout the night, for example), when the pressure may increase dramatically. Such periods of high pressure can cause several problems: excessive noise from high flow velocities, water hammer from quick closing taps or solenoid valves, plus the risk of water wastage is particularly great because higher pressure means higher flow rates. The water supply usually enters domestic dwellings beneath the kitchen sink so the first effect of high pressure is often experienced at that point; when the cold tap is turned on too quickly or too far, this creates a gush of water which hits the bottom of the sink and bounces back, soaking the user and creating a wet mess! The best way to control high pressure is by installing a pressure reducing valve. These take a high pressure at the inlet, then the valve reduces it to a lower pressure at the outlet as desired, under both flow and no-flow conditions. All Reliance pressure reducing valves are WRAS approved: this means that they have undergone independent third party testing to ensure that they comply with the current UK water regulations for pressure reducing valves. It also ensures that all materials used within the make-up of the valves have been verified as safe for potable water systems. How do pressure reducing valves work? Pressure adjuster Pressure Indicator Spring Valve housing Outlet Inlet Comb Valve Valve seat 315i Valve A pressure reducing valve is a valve which takes a high inlet pressure and reduces it to a lower outlet pressure. When it does this under both flow and no-flow conditions, the type of control is known as drop tight. Reliance s pressure reducing valves use a balanced spring and diaphragm to control the downstream pressure. This drop tight feature is one of the most important criteria for any pressure reducing valves, as this stops the pressure from creeping - a term which is used when an increase in the downstream pressure occurs under no flow conditions. A valve which will allow this creep cannot be known as 'drop tight' or in fact a true pressure reducing valve, as it will 2

eventually allow the pressure to creep up to equal the upstream pressure, which can cause significant problems and essentially negates the point of using a pressure reducing valve in the first place. The diaphragm effectively separates all of the water contact parts and the pressure from the water supply away from the control spring and associated mechanism. The body is then protected from debris by the use of a stainless steel strainer (as shown in the cutaway drawing below). Indicator Spring Inlet Outlet/s closed causing back-pressure Comb Valve closed Pressure Reducing Valve in closed position Under no flow conditions the downstream pressure puts back-pressure on the seat and diaphragm of the valve, which in turn overcomes the spring pressure. This means the seat moves up, forcing it to seal against the diaphragm, therefore not allowing the downstream pressure to increase. Indicator Spring Inlet Outlet/s open Comb Valve open Pressure Reducing Valve in open position Under flow conditions the back pressure against the seat is reduced thus allowing the seat to open and water to flow through the valve. 3

Unique Cartridge Design All Reliance pressure reducing valves use a cartridge system. The cartridge houses all working components of the pressure reducing valves: strainer, spring, diaphragm and seat. The cartridge format makes servicing or replacement of the valves as simple as possible. Each pressure reducing valve cartridge can be removed for servicing of the integral stainless steel strainer, which is situated at the base of the cartridge to protect the seat of the valve. If unprotected, debris could cause poor flow rates and even hold the seat in the open position thus preventing the pressure reducing valve from working properly. As all working components are incorporated in the one-piece cartridge, it continues to ensure that the set pressure is kept whilst servicing is being undertaken. Other valves may need to be re-commissioned after each service or, if they include several different components, it is easy for these to be misplaced. The cartridge system means complete replacement cartridges can be used for maintenance or repair, which minimises site down time and means only one spare cartridge needs to be held in stock rather than several small components. Some pressure reducing valves can be extremely noisy and cause annoyance, but each Reliance pressure reducing valve has been checked to ensure that any noise created does not exceed the 20dB limit: this is classed as a whisper on a decibel scale. Low noise is incorporated within the valve design so they comply with the European standard Class 1 BSEN 1567. The base of the cartridge has been specifically designed so that water will disperse, and thereby minimise noise. The comb also has a second significant purpose: by dispersing the water passing through the valve it alters the water flow turbulence, and this in turn reduces cavitations on the body of the valve. RWC-Syr Reliance has worked in partnership with the German manufacturer Syr for over 30 years and during these many years of experience we have built up a long lasting and productive relationship. Syr sets high standards: never content with current solutions, they are always pushing for a new improvement something even easier to install or more closely satisfying customer requirements. All valves are 100% tested to ensure quality is set to the highest standard. Both Reliance and Syr are ISO-9001 registered, which ensures systems are in place and followed to maintain quality at the highest standard. How to size a PRV This is predominantly based on two different criteria: application and flow rates. Application describes the type of property the valve is to be used in: whether it is commercial/industrial or a domestic installation. Flow rate is the most important factor for sizing a pressure reducing valve. Sizing a valve incorrectly can cause several problems; if oversized the valve seat may open for a very small flow rate, which may occasionally be acceptable but over a long period of time can result in a wire drawing across the valve seat. A wire drawing occurs when the valve disc and seat position operate close to the shut-off point of the valve for extended periods of time. This then means the water flow scores a pathway in the seat material which remains when the valve closes tight to the shut-off position and allows a little flow and pressure to creep through the valve. To calculate the flow rate you must work out how many outlets are required and what the combined maximum flow rate for these will be. You can then use the table to ascertain which size valve is required. Pressure Reducing Valve Sizing Guide Residential Building Commercial Building Size DN Max flow rate Vs Max flow rate Vs l/s l/s 15 0.5 0.5 20 0.8 0.9 25 1.3 1.5 32 2 2.4 40 2.3 3.8 50 3.6 5.9 65 6.5 9.7 80 9 15.3 100 12.5 23.3 125 17.5 34.7 150 25 52.8 200 40 92 250 75 139 4

For larger commercial applications various sizing solutions can be used: for example, if the flow rate is lower at some times than at others then using several smaller size PRVs in parallel may be more practical, or use one smaller valve as a bypass thus allowing water to flow easily through the valve when the flow rate is lower than normal, without causing either wire drawings or creating noise across the valve, as previously mentioned. Environmental Assessment Methods BRE Environmental Assessment Method is a scheme which has been developed to assess the environmental performance of buildings. It has become a recognised scheme which sets the standard for good practice in sustainable design. BREEAM is used by some planning authorities as a condition of planning permission, which helps the local planning authorities to guarantee the build will have incorporated best environmental practice. BREEAM certified buildings are designed for lower energy use and water consumption. Local authorities have more to gain from this scheme since evidence shows that most sustainable developments not only have a lower impact on the environment through lower running cost and reduced carbon emissions, but even experience lower rates of crime and demonstrate improved health amongst residents (The Prince's Foundation for the Built Environment, Valuing Sustainable Urbanism Report, 2007). To meet the BREEAM requirements the contractor and architects must look at all aspects of the build, and for each applicable one they can gain BREEAM points for use of sustainable products or practice. All allocated points are then totalled to a give a points rating based on the complete build, which is independently calculated, assessed and verified by a BREEAM approved assessor. More information about BREEAM is available at the website: www.breeam.org The Code for Sustainable Homes (CSH) goes further than the standard building regulations but is completely voluntary, and is only intended to help promote higher standards in new properties, through reducing carbon emissions and creating homes that are more sustainable. It applies within England, Wales and Northern Ireland. The code measures the sustainability of the property by rating it against nine categories, one of which is water. The aim in this category is to reduce the consumption of potable water in the home from all sources, including borehole well water, through the use of water efficient fittings and appliances and water recycling systems. Each category has a certain number of credits available and assessment criteria to ascertain if the new property complies; this is usually carried out through the use of site records and visual inspections. Included in the water category is a section on Water Reduction Devices, which can help achieve lower flow rates as part of the water efficiency calculator. This is also covered within Part G of the Building Regulations, in which the calculation procedure must be carried out in line with the Water Efficiency Calculator For New Dwellings: www.communities.gov.uk/publications/ planningandbuilding/watercalculator. The average household of 2 adults and 2 children uses 200m³ of water a year. By installing a pressure reducing valve you can dramatically lower this usage, but still keep the same comfort level. For example, by reducing the incoming water pressure from 6 to 3 bar there is a 30% reduction in the water usage, as shown in the graph. This reduction in water usage means that home-owners will benefit from lower water bills, and may help to gain certification under BREEAM and CSH. 100% Usage 20% Saving 30% Saving 5

Easiset 320 Domestic Pressure Reducing Valve A high quality pressure reducing valve, designed for domestic applications, incorporating a unique easy-to-use lift and turn adjustment mechanism. Features and Benefits High flow rate design Lift and Turn mechanism for ease of pressure adjustment One-piece Easiset cartridge Fully serviceable strainer Product Range Cold water up to 45 C PRED 320 001 ½" FBSP adjustable PRV 320F PRED 320 005 ¾" FBSP adjustable PRV 320F PRED 320 010 15mm adjustable PRV 320C PRED 320 015 22mm adjustable PRV 320C Hot water up to 80 C PRED 320 050 ½" FBSP adjustable PRV 320F PRED 320 055 ¾" FBSP adjustable PRV 320F PRED 320 060 15mm adjustable PRV 320C PRED 320 065 22mm adjustable PRV 320C Materials Body DZR brass Internal Components DZR brass Seals NBR elastomer Spring Zinc plated spring steel Stainless Steel NBR elastomer nylon mesh Cover Glass filled nylon polymer Dimensions H H L D 1/4" D 1/4" Approvals & Standards WRAS 0605101 DVGW BSEN 1567 Specifications Maximum working pressure 16bar Adjustable set pressure 1.5-5.5bar Pressure reduction ratio 10:1 Maximum working temperatures: Cold water version 45 C Hot water version 85 C Flow Characteristics L Size L (mm) H (mm) D (mm) DN15 FBSP 72 97 42 DN20 FBSP 74 97 42 15mm Comp 86 97 42 15mm Comp 88 97 42 Specify as Product code: PRED 320 (select appropriate) WRAS approved pressure reducing valve with lift and turn adjustment mechanism, full flow strainer and all working components contained in a cartridge form with downstream test point, suitable for domestic applications. 6

312compact Domestic Pressure Reducing Valve Range of domestic pressure reducing valves, compact in design and suitable for various applications. Features and Benefits Compact design Complete with gauge ports Cartridge Fully serviceable strainer Product Range PRED 312 010 15mm Adj 1.5-6.0bar 312compact PRV PRED 312 015 22mm Adj 1.5-6.0bar 312compact PRV PRED 312 020 ½" FBSP Adj 1.5-6.0bar 312compact PRV PRED 312 025 ¾" FBSP Adj 1.5-6.0bar 312compact PRV Dimensions Materials Body DZR brass Internal Components DZR brass Seals NBR elastomer Spring Zinc plated spring steel Stainless steel NBR elastomer nylon mesh Cover Glass filled nylon polymer A C A B D Approvals & Standards WRAS DVGW BSEN 1567 B Specifications Maximum working pressure 16bar Adjustable set pressure 1.5-6.0bar Pressure reduction ratio 10:1 Maximum Temperature 45 C Specify as Product code: PRED 312compact (select appropriate) WRAS approved pressure reducing valve, and all working components contained in a cartridge form with two downstream test points, one either side, suitable for domestic applications. A Flow Characteristics C A Part Code A B (mm) C (mm) D (mm) PRED 312 010 15mm 92 62 74 PRED 312 015 22mm 92 65 74 PRED 312 020 ½" FBSP 92 72 74 PRED 312 025 ¾" FBSP 92 76 74 D 7

315i Commercial Pressure Reducing Valve A range of commercial pressure reducing valves, incorporating a unique indicator so the set pressure can be identified easily without the need for a pressure gauge. Features and Benefits Easy-to-read pressure indicator Robust design Fully serviceable strainer Suitable for hot and cold supplies Product Range PRED 315 010 ½" MBSP Adj 1.5-6.0bar 315i PRV PRED 315 020 ¾" MBSP Adj 1.5-6.0bar 315i PRV PRED 315 030 1" MBSP Adj 1.5-6.0bar 315i PRV PRED 315 040 1¼" MBSP Adj 1.5-6.0bar 315i PRV PRED 315 050 1½" MBSP Adj 1.5-6.0bar 315i PRV PRED 315 060 2" MBSP Adj 1.5-6.0bar 315i PRV PRED 315 070 15mm Capillary Adj 1.5-6.0bar 315i PRV PRED 315 080 22mm Capillary Adj 1.5-6.0bar 315i PRV PRED 315 090 28mm Capillary Adj 1.5-6.0bar 315i PRV Dimensions C A B Part Code A (mm) B (mm) C (mm) PRED 315 010 130 74 103 PRED 315 020 138 74 103 PRED 315 030 170 84 132 PRED 315 040 191 94 194 PRED 315 050 220 94 194 PRED 315 060 255 94 187 PRED 315 070 104 74 103 PRED 315 080 124 74 103 PRED 315 090 148 84 132 8

Materials Body DZR brass Internal Components DZR brass Seals EPDM Stainless steel EPDM Cover ABS Approvals & Standards WRAS DVGW BSEN 1567 Specify as Product code: PRED 315 (select appropriate) WRAS approved pressure reducing valve with full flow strainer and all working components contained in a cartridge form, with two downstream test points. Clear pressure indicator on side of cartridge. Suitable for commercial applications. Specifications Maximum working pressure 25bar Adjustable set pressure 1.5-6.0bar Pressure reduction ratio 10:1 Maximum temperature 70 C Flow Characteristics 70% back pressure Open outlet Red = 15mm / 1/2 Blue = 22mm / 3/4 Green = 25mm / 1 7 6 Pressure Drop (Bar) 5 4 3 2 1 0 0 20 40 60 80 100 120 140 160 180 200 Flow Rate (l/min) 9

6247 Commercial/Industrial Pressure Reducing Valve High flow rate pressure reducing valve, which provides accurate pressure control for commercial or industrial applications. Features and Benefits Accurate pressure control Robust design One piece cartridge Upstream and downstream test points Product Range PRED 624 001 DN65 Adjustable 6247 PRV PRED 624 002 DN80 Adjustable 6247 PRV PRED 624 003 DN100 Adjustable 6247 PRV Materials Body Cover Seals s Spring Bronze ABS plastic EPDM EPDM Stainless steel Stainless steel Dimensions A C B Part Code A (mm) B (mm) C (mm) PRED 624 001 283 290 185 PRED 624 002 283 310 200 PRED 624 003 283 350 220 10

Approvals & Standards WRAS DVGW BSEN 1567 Specifications Maximum working pressure 16bar Adjustable set pressure 1.5-6.0bar Maximum Temperature 45 C 0.25mm Flange PN16 Media Water/Compressed air Specify as Product code: PRED 624 (select appropriate) WRAS approved pressure reducing valve, with in-line cartridge and full flow coaxial strainers, and all working components contained in a single cartridge. PN16 Flanged. Flow characteristics 11

PRESSURE REDUCING VALVES Reliance Water Controls Ltd A Reliance Worldwide Company Worcester Road, Evesham, Worcestershire, WR11 4RA, UK UK - Freephone: 0800 389 5931 Freefax: 0800 389 5932 Outside UK - Tel: +44 (0) 1386 712400 Fax: +44 (0) 1386 712401 Email: sales@rwc.co.uk Reliance has prepared the content of this document carefully but disclaims all warranties, express or implied, as to the accuracy of the information contained herein. Reliance reserves the right to make changes to the product and the information contained in this document at any time. PRV-001-04/11 Reliance Water Controls Ltd 2011